1. Field of the Invention
The present invention generally relates to blades for graders, snow plows and the like and, more particularly, is concerned with a grader blade which incorporates a pair of tiered inserts adapting its bottom forward edge for improved impact and downpressure wear resistance.
2. Description of the Prior Art
Graders and snow plows are both well known and each have a relatively long moldboard which extends generally laterally of the surface being worked and is moved over the surface in a direction generally perpendicular to the length of the moldboard. It is conventional practice to mount a grader blade made of steel on the lower edge of such moldboard with the blade, in turn, extending downwardly below the moldboard lower edge and itself having a lower edge forming the working surface of the blade.
Grader blades made of steel have the advantage of being relatively inexpensive, but also the disadvantage of wearing out extremely rapidly. Once worn out, the steel blade must be replaced to avoid damage to the moldboard itself. The replacing of the steel blade is, of course, time consuming and also represents downtime for the equipment. Thus, over the years, various techniques, such as impregnation and hardfacing of the blade cutting edge with carbide particles, and attachment of cemented carbide inserts into or onto the blade edge have been employed in attempting to prolong the life of the steel blade. Some of these prior art techniques are used with blades disclosed in U.S. Pat. Nos. to Russell et al (1,922,917), Stephenson (3,529,677), Jackson et al (3,790,353), Beiswenger (3,971,323), Toews (3,888,027), Stephenson et al (3,934,654) and Moen et al (4,052,802), and a blade identified as Kengard A grader blade manufactured by Kennamental Corporation.
While many of these prior art blades would appear to operate reasonably well under the limited range of operating conditions for which they were designed, most seem to embody one or more shortcomings in terms of complexity, performance, reliability and cost effectiveness which make them less than an optimum design. Consequently, a need exists for a different approach to grader blade design, one which will more adequately address the kinds of wear and forces encountered by the lower end of the grader blade.